Hands-on experiments in physics at sercondary school C.I.S. Alves, S.A.S. Rodrigues, A.C.C.C. Amorin, M. J. M. Gomes, M. Pereira and M.S.V. Machado 3rd International Conference on Hands-on Science-Science Education and Sustainable Development, 4-6 September 2006, Braga, Portugal, (Experimental Demonstrations).